History:The First Generation Colt Single Action Army revolvers were produced between
their introduction in 1873 and WWII. Production resumed in 1956, and these
guns are known as "Second" generation Single Action Army revolvers, which are
quickly identified by a "SA" suffix at the end of their s/n, and continued
through 1975. In 1976 a "Third"generation of Colt Single
Action Armys was introduced. On these, the "SA" marking is moved to
the front of the serial number.

These guns carried a varied number of names, from 1873 for
the year it was introduced. The Peacemaker was another name used by the
old west community. Single Action Army was what the military used when the
guns were issued to the cavalry. The factory even today uses model
designations of the alphabet & this model was the "P".

Calibers & Configurations:
The .45 Colt chambering was by far the most popular, accounting
for nearly half of the pre-WWII SAA's. The "Winchester Centerfire" calibers –
.44 WCF (44-40), .38 WCF (38-40), and .32 WCF (32-20) placed 2nd, 3rd & 4th in
popularity; doubtless in part due to the fact that paired with an 1873 or 1892
Winchester they allowed the usage of the same cartridge in both rifle and
revolver, simplifying supply logistics. The obsolete .41 Colt was the only
other caliber produced in significant quantity, although a number of other
chamberings were available on special order. Other calibers as 38 Special
& 44 Special were among those included. Standard barrel lengths were
7-1/2", 5-1/2", and 4-3/4", with others available on special order.

Special guns made without ejector rods or housings were
called "Sheriff's Models" or "Storekeepers Models", and often had shorter than
standard barrels. The SAA was used by the US military from it's introduction
through the Spanish American War & Philippine insurrection. The original 7-1/2"
barrel martial version is called the "Cavalry Model" by collectors. Many
military SAA's were refurbished by Springfield Armory or Colt for reissue with a
shorter 5-1/2" barrel, and these are called "Artillery Models" today. The Bisley
model was introduced in the 1890's, and featured a redesigned grip & hammer.

Later in the 3rd generation series the New Frontier was
introduced with a more squarer top strap of the frame for accommodation of
adjustable rear sights plus a ramped base & front sight.

Colt model
1873, also known as the Single Action Army, or the "P" model at the
factory.
This gun happens to be a 1st Generation

Barrels: The
threads on the 1st & 2nd generation guns used a 20 thread per inch threads.
On the later 3rd generation the barrel threads were changed to a finer pitch.

Cylinders: Also the cylinder ratchets
were made differently, thus requiring other component parts that mate to &
function with the cylinder to be also altered. The new cylinder
eliminated the integral base pin bushing. When we refer to Old Style or
New Style, we are actually meaning the Old Style as being either the 1st or 2nd
generation, while the New Style as the 3rd generation.

Bolts / Cylinder Stops: The
technical factory name for these parts is a "Bolt" or probably a locking bolt.
Many non gunsmithing persons call them a cylinder stop. This part
was used unchanged until 1976 when the 3rd generation version was brought out.
The original part number was #50976. After the change the part number was
not changed, but the configuration of the part did. It was simply
designated the "Old Style' or the "New Style"

Listed below
are the various styles encountered. Those of you who are trying to find a
replacement part for the aftermarket "Clones" may well have to take the firearm
in question apart & compare the broken part with these CAD drawings of the Colt SAA. The Old Style & New Style are exact replacements for the Colt
firearm.

The Modified Style was a composite of both including the
thicker rear bottom of the NS plus the extended tail of the OS & was
designed to fit about any model out there, whether it be a clone or a worn Colt.
These Modified Styles cylinder stops will HAVE to be fitted to each gun.
As far as we know, we at Wisner's Inc. are the only ones making this specific
modified interchangeable part which should be able to be fitted to the clones.
This modified version is made with the bottom section below the pivot hole
thicker like the New Style, but with the tail shape & length of the Old Style &
then the tail is lengthened by about .020. This configuration will fit
most all the clones & of course even some of the worn old original SAAs.

Old Style
#50976 OS

New Style
#50976 NS

Modified Style
#50976 M

These bolts are made in a standard thickness of .152.
Wisner's Inc. makes an oversize thickness of .160 to be used on old worn
cylinder locking notches.

All of these parts need to be hand fitted to the individual
firearm. They are not just a drop in part, even the factory
replacement parts were not. The RH tail need not be fitted, other than
stoning the back side to allow it to function smoothly. The inner (LH)
tail end needs to be fit to the hammer stud so it is timed to slide off the
stud's angle as the hammer is cocked, just as the cylinder is rotated with the
locking notch in line with the bolt at the full cocking motion of the hammer.

Once the bolt is in line with the cylinder notch & the bolt's
tail slips off the hammer stud, the bolt's inner radiused face will drop into
place with the hammer's stud now that the hammer is rearward & locked into the
fire sear notch of the hammer.

Before all this can take place, the hammer has to have proper
sear notches, & the stud has to be correct for timing. The trigger
also needs to be in good shape to mate with the hammer notch for proper timing.
Also the cylinder base pin & bushing need to be fitted so not excess slop is
there for endshake looseness.

Hands: The
hands were also changed at the 3rd generation as shown below.

Old Style
#51000

New Style
#52770

Sear & Bolt Spring: The
sear & bolt spring is as flat, dual tailed spring held in place by one screw.
It places tension on both the trigger & the bolt. The original thickness
of this spring is .045. Aftermarket springs of a medium strength are
made in .035 while a light weight version is made in .025. The .035 would
be the common one used to lighten up the average shooter firearm.

Mainspring: The
mainspring is a flat arched leaf spring that has a slight groove on the upper
forward end for the hammer roller to ride in. The original material was
.062 thick & machined to a taper (top to bottom) to make it like a buggy whip
for the 1st & 2nd generation guns. The 3rd generation saw the same spring,
but no taper, making it a heavier pull on the hammer.

Replacement mainsprings are usually made slightly long so
they can be fitted to about any version, even the many copies or clones.
If they are not properly fitted, when the hammer is pulled to the rear to full
cock, the front tip section may bind in the inner arc of the hammer & create a
stiff resistance because it is being stopped by the mainspring front. This
situation makes for a hard cocking firearm PLUS it can very well break the tip
off the mainspring.